Ignition sparking plug for internal-combustion engines



F. L. RAPSON. IGNITION SPARKING PLUG F0 APPLICATION 1,399,797.

Patented Nov. 29, 1921.

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nairae erase earner FREDERICK LIONEL RAPSON, OF LIVERPOOL, ENGLAND.

IGNITION SPARRING PLUG FOB INTERNAL-COBIBUSTION' ENGINES.

Specification of Letters Patent.

Patented Nov. 29, 1921.

Application filed. October 16, 1918. Serial No; 258,428.

Improvements in or'Relating to Ignition "Sparking Plugs for Internal-Combustion Engines, of which the following isa specification.

This invention relates to improvements in ignition sparking plugs for internal combustion engines.

The chief object of this invention is to provide a sparking plug with an automatically operated cleaning device whlch will prevent the plug from sooting or getting covered with oil and thereby impairing its efiiciency.

A further object is to provide means whereby the cleaning device may be easily removed should it require attention, without interfering with the porcelain non-conductor and asbestos packing which is permanently fixed in the casing and nonleaking.

A still further object is to provide in combination with a sparking plug of the above type improved means for cooling the electrodes.

\Vith these and other objects in view the invention consists chiefly in providing a sparking plug with a movable member disposed between'sparking points or surfaces which member is adapted to be actuated automatically to keep the said sparking points or surfaces clean. I

The invention also consists in providing in the outer casing of the sparking plug a number of openings which are adapted to be opened or closed by the reciprocatlon of the cleaning member to admit air for cooling the inner electrode during the. interval between the sparking of the said plug.

The invention will now be described with reference to the accompanying drawings in which Y Figure 1 is a longitudinal sectional elevation. t

Fig. 2 is a cross section taken on the line A-A; and

Fig. 3 is an inverted plan of one form of the invention.

As shown the sparking plug comprises a central rod or terminal 1 threaded at one end 2 to receive the usual conductor binding nuts 3 and at its other or'lower end to reoeive a member 4 which is coned or flared outwardly to provide a'- series of circumferential points 5 inthe' form of a star having preferably three points or projecting surfaces. Adjacent to and-surrounding this star at its lower and enlarged end is a preferably steel annular conductor or sparking terminal 6 which is'disposed in the lower end, 7 of the casing 8 of the sparking plug, a suitable interior flange .9 being provided on the casing 8 to keep the conductor in position. The lower and reduced end 7 of the cas1ng8 is threaded in the usual manner to screw into anengine cylinder casing and a suitable asbestos washer 10 is provided to A hexagonal enlarge make a secure joint. ment or nut 11 is formed on the upper end of the casing 8to enable the plug to be screwed in'position by a spanner. Within the casing 8 and surrounding the :inner rod or terminal 1 is-aporcelain or like insulating sleeve 12 which is coned externally at its inner or lower endas shown at 13 to abut against a coned face or faces formed .on the interior of the outer annular conductor or sparking terminal 6. A cylindrical. recess 14 is formed in the said lower end of the insulating sleeve 12' and within this recess is slidably mounted a cleaning member 15 which is adapted to be normally pressed outwardlyzby a coiled spring 16 surroundlng the' nner terminal rod land abutting at one end against the said cleaning member 15 and at its other end against a washer 17 secured to the inner terminal rod 1. which is constructed of metal or of non-conducting material is formed wlth a chamber The annular cleaning member 15 j 18 at its lower end to receive the compressed mixture. on the compression stroke of the engine, and thus facilitate the upward move ment of the said cleaning member against the action of'the spring 16. The lower or outer annular 'end of the cleaning member 15 is formed with suitably shaped rubbing surfaces 19 which are adapted to prevent any carbon or soot deposits on the inner and outer sparking points, surfaces or terminals.

A flanged non-conducting sleeve 20 'is screwed onto the star member a to limit the downward movement of the cleaning member 15. The star member 4 is positively secured to the rod 1 by a lock nut 21. Thus the cleaning member 15 can be removed from the lower end of the plug to replace the spring 16 when worn by unscrewing the member A and the lock nut 21 from the rod 1. Adjacent to the upper end of the cleaning member 15 and in the casing 8 and non conducting sleeve 12 is formed a number of openings or orifices 22 leading to the atmos phere through which air is adapted to pass into the interior of the plug to cool the inner electrode 1 when the cleaning member 15 is in its lowest or normal position. When the member 15 is raised against the action of the spring 16, during the compression stroke of the engine and when the ignition takes place across the spark gap, these openings 22 are closed. After the sparking has taken place the spring 16 will move the member 15 outwardly and thereby clean the sparking terminals. The cleaning member 15 is provided with an outer groove or grooves 23 for the reception of packing material 24, and packing material 24: is provided between the inner electrode 1 and the said member 15 to prevent the mixture from escaping to the upper portion of the plug and to the atmosphere. A suitable gland 25 is screwed into the cleaning member 15 to hold the said packing in position. Any suitable means may be provided to guide the cleaning member such as a plurality of rods 26 depending from the disk 17 secured to the inner electrode 1 and adapted to engage in holes 27 cut in the upper end of the cleaning member 15 or guides may be formed on the rod 1 of the inner electrode to slide in grooves cut in the cleaning member 15. As bestos or like packing 28 is provided in the upper end of the casing 8 and on the upper end of the'insulating sleeve 12 and this packing 28 is compressed by a washer 29 and a nut 30 screwed on the threaded end of the inner rod or terminal 1. The upper or outer end of the casing 8 is closed by a suitably shaped cover 81 of porcelain, or other non-conducting material, and upon this cover 31 is disposed a fiber or like washer 32 which is held in position by a nut 33 screwed onto the threaded end of the inner terminal or rod 1.

WVhen the above described sparking plug is used on a four stroke engine, the cleaning member will protect-the spark points during the firing, exhaust and suction strokes of the engine and lift only on the latter portion of the compression stroke, thereby allowing the sparking to take place. By utilizing the above device it is anticipated that misfires will be entirely eliminated and that the life of sparking plugs will be prolonged as these would only require attention periodically for instance when the valves of the engine needed grinding in. r

What I claim is '1. A spark plug comprising a shell, a central electrode having a sparking point spaced from the shell, 1nsulation between the central electrode and the shell, an automatically reciprocal cleaning member mounted on the central electrode to clean the surface on the shell adjacent the sparl ing point, a spring for normally holding the cleaning Inemberover the sparking surface on the shell and guides for the reciprocal cleaning member.

2. A spark plug comprising a shell, a central electrode having a sparking point adjacent the shell, a cleaner normally located over the surface of the shell adjacent the sparking poi ntand adapted to be moved over said surface to clean the latter ing pointcooperative position, and means arranged between said member and insulating section to operate the member toward the sparking points when the pressure within the cylinder has been released.

4-. A spark plug comprising a shellyan insulating section arranged therein, an electrode carried thereby, a rod extending longitudinally of the insulatingsectioma second electrode carried thereby, a member movable within a recess formed in the insulating section and having'one end formed to cooperate with both electrodes for cleaning the same, a sleeve fixed with relation to the rod and adapted to limit movement of the member in one direction to a position cooperative with both electrodes, and a spring operative when compressed to move the member toward the electrodes for cleaning the same, the plug being formed with apertures to admit air to the recess of the insulating section above the member, said member closing the apertures when operated FRED. LIONEL RAPSON. 7 

